1. Field of the Invention
The present invention relates to a novel copolymer and more particularly a novel copolymer comprising an acrylate or methacrylate ester having a fluoroalkyl group, a polyalkylene glycol acrylate or methacrylate, an acrylate or methacrylate ester having a hydroxyl group and a compound selected from alkyl acrylates, alkyl methacrylate and butadiene, which copolymer can be used as a desoiling agent.
2. Description of the Related Art
Hitherto, it is known that a copolymer of an acrylate or methacrylate ester having a fluoroalkyl group (hereinafter, sometimes referred to as "fluorine-containing compound") with polyalkylene glycol acrylate or methacrylate and optionally an alkyl acrylate or methacrylate is used as a desoiling agent which imparts water- and oil-repellency to fabrics and makes it easy to remove adhered soils from the fabrics during washing or dry cleaning (cf. Japanese Patent Kokai Publication No. 134786/ 1978). In a copolymer useful as a desoiling agent, a polyethylene glycol-containing compound appears to assist a detergent in removing soils easily.
A homo- or co-polymer of the fluorine-containing compound is known as a water- and oil-repellent which imparts water- and oil-repellency to articles such as fibers and prevents penetration of oily stains in the articles. However, some fluorine-containing polymers which have much stronger water-repellency which cause the detergent to become ineffective during washing, and make it difficult to release the adhered soils from the fabrics, that is, the polymers decrease the desoiling nature of the articles. Further, such polymers deteriorate the inherent water-absorbance of the fabrics, which the feeling of the fabrics to become worse. To facilitate the release of soils from the fabrics and to keep the good feeling of the fabrics, other desoiling agent which can impart large water-absorbance to the fabrics is often additionally employed. However, such desoiling agent renders soils to adhere easily to the fabrics and tends to liberate from the fabrics.
To improve the resistance of water- and oil-repellency to washing, it is proposed to copolymerize the fluorine-containing compound with an acrylate or methacrylate ester having a hydroxyl group and optionally an alkyl acrylate or methacrylate (cf. Japanese Patent Publication No. 3798/1975 and U.S. Pat. No. 3,356,628).
However, the copolymer comprising the acrylate or methacrylate ester having the hydroxyl group or a hydrophilic group such as polyethylene glycol group and the acrylate or methacrylate ester having the fluoroalkyl group has little durability of soil-releasability and water-repellency against washing, although it has good initial soil-releasability and water- and oil-repellency.